Imaging devices, such as printing devices and all-in-one devices that scan, print, and copy, utilize motors to drive paper feed mechanisms, move imaging, scanning, and printing units, and/or enable servicing systems such as printhead wipers, printhead capping devices, and printhead cleaning systems. These are only a few examples of how motors may be utilized within an imaging device. Many such devices are designed such that more than one system function is coupled to the same motor so that fewer motors are needed to support the multiple system functions. Typically, imaging devices have been developed with three motors and with a corresponding application specific integrated circuit (ASIC) configured to control the three motors.
The motor control ASIC is implemented with an H-bridge circuit structure that enables a microprocessor or controller to independently control each motor in an imaging device. The ASIC includes one H-bridge circuit for each motor being controlled, and for a typical three-motor device, the ASIC will include three H-bridge circuits. With the advent of two-motor imaging devices, two H-bridge circuits of the ASIC will be utilized to control the two motors while the third H-bridge circuit goes unutilized.
The motor control ASIC with the three H-bridge circuit structure continues to be implemented in two-motor imaging devices because it would not be cost effective to design a specialized ASIC with only two H-bridge circuit motor drives, particularly when taking into account the large volume purchase discounts for high volume devices. The small savings in component costs, as well as the savings that would otherwise be incurred for additional engineering and design costs to produce a specialized ASIC, are significant with the high volume sales of such devices. It is cost effective and beneficial to design and utilize an ASIC which can be implemented for similar, yet different devices, such as two-motor and three-motor imaging devices. However, it would also be beneficial if the third H-bridge circuit of an ASIC in a two-motor device could be utilized for component and/or system functionality in the device rather than go unutilized as a motor control.